DAY2SVR: Nws Storm Prediction Center Norman Ok

ACUS02 KWNS 050459
SWODY2
SPC AC 050457

DAY 2 CONVECTIVE OUTLOOK
NWS STORM PREDICTION CENTER NORMAN OK
1157 PM CDT THU OCT 04 2012

VALID 061200Z - 071200Z

...NO SVR TSTM AREAS FORECAST...

...SYNOPSIS...
BLOCKING APPEARS LIKELY TO REMAIN PROMINENT WITHIN THE LARGE-SCALE
UPPER FLOW PATTERN NEAR/WEST OF THE PACIFIC COAST THROUGH THIS
FORECAST PERIOD. TO THE EAST OF THIS REGIME...CONFLUENT BELTS OF
WESTERLIES ACROSS THE ROCKIES WILL MERGE INTO BROAD UPPER TROUGHING
EXTENDING EASTWARD THROUGH THE ATLANTIC SEABOARD. WITHIN THIS
CYCLONIC FLOW...MODELS INDICATE THAT ONE SIGNIFICANT SHORT WAVE
TROUGH WILL LIFT THROUGH THE EASTERN CANADIAN PROVINCES/LOWER GREAT
LAKES AND NORTHEASTERN STATES DURING THIS PERIOD...WHILE ANOTHER
DIGS INTO THE CENTRAL PLAINS...BEFORE TURNING EASTWARD THROUGH THE
MIDDLE MISSISSIPPI VALLEY. IN RESPONSE TO THESE DEVELOPMENTS...A
COLD FRONT IS EXPECTED TO CONTINUE AN EASTWARD/SOUTHWARD PROGRESSION
THROUGH THE ATLANTIC SEABOARD/GULF STATES AND RIO GRANDE
VALLEY...WHILE THE CENTER OF A LARGE SURFACE HIGH SHIFTS SOUTHWARD
TO THE LEE OF THE CENTRAL ROCKIES...INTO THE SOUTHERN HIGH PLAINS.

...SRN PLAINS/OZARK PLATEAU INTO MID ATLC COAST/SRN NEW ENGLAND...
LOWER/MID TROPOSPHERIC FORCING FOR UPWARD VERTICAL MOTION ASSOCIATED
WITH THE UPPER IMPULSES WILL GENERALLY REMAIN WELL TO THE COOL SIDE
OF THE FRONTAL ZONE. HOWEVER...MOISTURE ABOVE THE SURFACE-BASED
STABLE LAYER...COUPLED WITH MODESTLY STEEP MID-LEVEL LAPSE
RATES...PARTICULARLY FROM THE SOUTH CENTRAL PLAINS THROUGH PARTS OF
THE OZARK PLATEAU AND TENNESSEE VALLEY...MAY CONTRIBUTE TO
SUFFICIENT INSTABILITY FOR SCATTERED THUNDERSTORMS. FARTHER
NORTHEAST...WEAK ELEVATED CONVECTION MAY BE ONGOING AT 12Z SATURDAY
IN ASSOCIATION WITH THE LEAD IMPULSE ACROSS PARTS OF THE OHIO
VALLEY...BEFORE FORCING WEAKENS/SHIFTS OFF TO THE NORTHEAST.

OTHER...WIDELY SCATTERED STORM DEVELOPMENT MAY NOT BE OUT OF THE
QUESTION SATURDAY AND SATURDAY EVENING...ALONG OR JUST AHEAD OF THE
COLD FRONT...FROM PARTS OF SOUTHERN NEW ENGLAND INTO THE LEE OF THE
SOUTHERN APPALACHIANS. HOWEVER...DUE TO WEAK INSTABILITY AND
GENERALLY WEAK MID/UPPER FORCING FOR UPWARD VERTICAL MOTION...SEVERE
WEATHER POTENTIAL STILL SEEMS NEGLIGIBLE AT THE PRESENT TIME.

...FLORIDA AND ADJACENT S ATLC COAST...
IMPULSES WITHIN A RESIDUAL MOIST PLUME ON THE PERIPHERY OF A
WEAKENING SOUTHWESTERN ATLANTIC SUBTROPICAL HIGH CENTER MAY
CONTRIBUTE TO SCATTERED THUNDERSTORM ACTIVITY SATURDAY.

..KERR.. 10/05/2012

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